Não informado. (1927). Bulletin of the International Bureau of Education. International Bureau of Education.
Chicago-referens (17:e uppl.)Não informado. Bulletin of the International Bureau of Education. Geneve, Suíça: International Bureau of Education, 1927.
MLA-referens (8:e uppl.)Não informado. Bulletin of the International Bureau of Education. International Bureau of Education, 1927.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.